The behaviour of materials in the case of impingement with high-energy gas jets is always of importance if materials are selected for applications, in which said gas jets occur or might occur.
This is, for example, the case in materials, which form the surface of a missile's seeker head. These materials must maintain transparency even in case of high Mach numbers. Typically, the relevant material properties are to be maintained for a limited period only, since impingement with high-energy gas jets actually also occurs for a short period only. Thus, it is in principle sufficient to carry out impingement with a high-energy gas jet for a limited period of time when the materials are tested.
A test device according to the type described above is known from U.S. Pat. No. 5,207,388. This older U.S. Patent describes the testing of materials, which are exposed to high thermal and pressure stress, such as in space missiles, by impinging a material sample with a high-energy gas jet. Particularly, the older U.S. Patent refers to the design of a nozzle which forms the output of a plasma torch and which directs the high-energy gas jet onto the sample.
This and other known test devices for impinging a sample with a high-energy gas jet are characterized by a stationary structure. A certain period of time passes during each individual test until the gas jet, hitting the sample, has stabilized and until defined impinging conditions are present. Uncontrolled conditions also occur during switch-off of the gas jet, after the actual test has been completed. Starting and stopping the test device have particularly negative effects if a defined impingement with the gas jet is to be carried out for a very short period only.
Other known test devices for impinging a sample with a high-energy gas jet are based on wind tunnels or test sledges, which are normally used for detecting aerodynamically derived forces. Operation of wind tunnels or test sledges for impinging a sample with a high-energy gas jet is extremely cost-intensive.